a) đặt A=\(\sqrt{2+\sqrt{3}}\)

=>    \(\sqrt{2}.A=\sqrt{4+2\sqrt{3}}=\sqrt{\left(\sqrt{3}+1\right)^2}\)

=>     A = \(\frac{\sqrt{6}+\sqrt{2}}{2}\)

ý b là nhân thêm 2 vào r lm tương tự nha bn ! 

\(2x-5\sqrt{x}+2=0\)

\(\Leftrightarrow-5\sqrt{x}+2=0-2x\)

\(\Leftrightarrow-5\sqrt{x}+2=-2x\)

\(\Leftrightarrow-5\sqrt{x}=-2x-2\)

\(\Leftrightarrow\left(-5\sqrt{x}\right)^2=\left(-2x-2\right)^2\)

\(\Leftrightarrow25x=4x^2+8x+4\)

\(\Leftrightarrow4x^2+8x+4=25x\) (chuyển vế)

\(\Leftrightarrow4x^2+8x+4-25x=0\)

\(\Leftrightarrow4x^2-17x+4=0\)

\(\Leftrightarrow x\left(4x-1\right)-\left(4x-1\right)=0\)

\(\Leftrightarrow\left(4x-1\right)\left(x-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}4x-1=0\\x-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{4}\\x=1\end{cases}}\)

Vậy nghiệm phương trình là: \(\left\{\frac{1}{4};1\right\}\)

ĐK:\(x\ge0\)

pt\(\Leftrightarrow\left(2x-4\sqrt{x}\right)-\left(\sqrt{x}-2\right)=0\Leftrightarrow2\sqrt{x}\left(\sqrt{x}-2\right)-\left(\sqrt{x}-2\right)=0\)

\(\Leftrightarrow\left(2\sqrt{x}-1\right)\left(\sqrt{x}-2\right)=0\Rightarrow\orbr{\begin{cases}2\sqrt{x}-1=0\\\sqrt{x}-2=0\end{cases}\Rightarrow\orbr{\begin{cases}\sqrt{x}=\frac{1}{2}\\\sqrt{x}=2\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{1}{4}\\x=4\end{cases}}}\left(TMĐK\right)\)

Vậy....

GTLN ak. bạn có nhầm đề k vậy, bạn xem lại đề đi.

mình k ak

bạn giúp mình phân tích cái kia ra là đc

\(a,\left(1+\frac{a-\sqrt{a}}{\sqrt{a}-1}\right)\left(1-\frac{a+\sqrt{a}}{1+\sqrt{a}}\right)=\left(1+\frac{\sqrt{a}\left(\sqrt{a}-1\right)}{\sqrt{a}-1}\right)\left(1-\frac{\sqrt{a}\left(\sqrt{a}+1\right)}{\sqrt{a}+1}\right)\)

\(=\left(1+\sqrt{a}\right)\left(1-\sqrt{a}\right)=1^2-\sqrt{a}^2=1-a\)

\(b,\left(2-\frac{a-3\sqrt{a}}{\sqrt{a}-3}\right)\left(2-\frac{5\sqrt{a}-\sqrt{ab}}{\sqrt{b}-5}\right)=\left(2-\frac{\sqrt{a}\left(\sqrt{a}-3\right)}{\sqrt{a}-3}\right)\left(2-\frac{-\sqrt{a}\left(\sqrt{b}-5\right)}{\sqrt{b}-5}\right)\)

\(=\left(2-\sqrt{a}\right)\left(2+\sqrt{a}\right)=2^2-\sqrt{a}^2=2-a\)

\(c,\left(3+\frac{a-2\sqrt{a}}{\sqrt{a}-2}\right)\left(3-\frac{3a+\sqrt{a}}{3\sqrt{a}+1}\right)=\left(3+\frac{\sqrt{a}\left(\sqrt{a}-2\right)}{\sqrt{a}-2}\right)\left(3-\frac{\sqrt{a}\left(3\sqrt{a}+1\right)}{3\sqrt{a}+1}\right)\)

\(=\left(3+\sqrt{a}\right)\left(3-\sqrt{a}\right)=3^2-\sqrt{a}^2=3-a\)

\(d,\left(\frac{a-\sqrt{a}}{\sqrt{a}-1}+2\right)\left(2-\frac{\sqrt{a}+a}{1+\sqrt{a}}\right)=\left(\frac{\sqrt{a}\left(\sqrt{a}-1\right)}{\sqrt{a}-1}+2\right)\left(2-\frac{\sqrt{a}\left(\sqrt{a}+1\right)}{\sqrt{a}+1}\right)\)

\(=\left(\sqrt{a}+2\right)\left(2-\sqrt{a}\right)=2^2-\sqrt{a}^2=2-a\)

 \(a,\sqrt{12}+2\sqrt{27}+3\sqrt{75}-9\sqrt{48}=2\sqrt{3}+6\sqrt{3}+15\sqrt{3}-36\sqrt{3}\)

\(=-13\sqrt{3}\)

\(b,2\sqrt{3}.\left(\sqrt{27}+2\sqrt{48}-\sqrt{75}\right)=2\sqrt{3}\left(3\sqrt{3}+8\sqrt{3}-5\sqrt{3}\right)\)

\(=2\sqrt{3}.6\sqrt{3}=36\)

\(c,\left(2\sqrt{2}-\sqrt{3}\right)^2=8-4\sqrt{6}+3\)

\(=11-4\sqrt{6}\)

\(d,\left(1+\sqrt{3}-\sqrt{2}\right)\left(1+\sqrt{3}+\sqrt{2}\right)=1+2\sqrt{3}+3-2\)

\(=2+2\sqrt{3}\)

\(\sqrt{x^2+3x+3}=1\)

\(\Leftrightarrow x^2+3x+3=1\)

\(\Leftrightarrow x^2+3x+2=0\)

\(\Leftrightarrow x^2+x+2x+2=0\)

\(\Leftrightarrow x\left(x+1\right)+2\left(x+1\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x+1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+2=0\\x+1=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=-2\\x=-1\end{cases}}\)

\(2\sqrt{x+2+2\sqrt{x+1}}-\sqrt{x+1}=4\)

\(\Leftrightarrow2\sqrt{x+1+2\sqrt{x+1}+1}-\sqrt{x+1}=4\)

\(\Leftrightarrow2\sqrt{\left(\sqrt{x+1}+1\right)^2}-\sqrt{x+1}=4\)

\(\Leftrightarrow2\left(\sqrt{x+1}+1\right)-\sqrt{x+1}=4\)

\(\Leftrightarrow2\sqrt{x+1}+2-\sqrt{x+1}=4\)

\(\Leftrightarrow\sqrt{x+1}=2\)

\(\Leftrightarrow x+1=4\)

\(\Leftrightarrow x=3\)